Centrifuges, in particular air-cooled laboratory centrifuges, frequently develop significant background noise, which is sometimes significant, in operation, which is perceived as annoying by individuals located nearby. The causes of the sometimes significant background noise during operation of centrifuges are extraordinarily manifold. Thus, for example, even extremely small imbalance weights in the centrifuge vessel result in a vibration of the centrifuge, which finally causes the development of rattling sounds or similar noise. In addition, the rotor chamber is also responsible for a majority of the noise development of a centrifuge. The fundamental construction of a rotor chamber for a centrifuge is known from the prior art. It provides a typically cylindrical chamber for receiving the rotor. The rotor chamber is typically implemented as open on top for the introduction and removal of samples to be centrifuged and/or for changing the rotor. In contrast, the base area is typically implemented as essentially closed except for a passage for a drive shaft and is fixedly connected to the side wall of the rotor chamber. Overall, the rotor chamber thus has a trough-shaped profile in cross-section. Furthermore, the centrifuge typically comprises a pivotable lid, using which the inner space of the centrifuge comprising the rotor chamber can be closed on top.
The rotor rotating in the rotor chamber of the centrifuge is frequently also implemented so that in the rotating state, it provides cooling air for cooling the attached centrifuged material and the other components situated in the inner area and optionally also the components lying further in the outside area, depending on the guiding of the cooling air. However, in particular this airflow results during operation of the centrifuge in interference with the rotor flow propagating as sound waves under certain circumstances, which is acoustically perceptible as a discrete tone. The excitation of the rotor chamber to vibrations, which in turn generate airborne noise in the surrounding air, caused by the rotation of the rotor, is the origin of the occurrence of this tone.
Fundamental measures for reducing the total balance of the noise development of a centrifuge are already known in the prior art. Thus, for example, the flapping noises caused by the vibration of the centrifuge and/or the housing may be reduced, inter alia, by the use of appropriate elastic bearings, cushioned feet, etc. A further possibility is known from DE 197 19 959 C1, which discloses a laboratory centrifuge, comprising, inter alia, a base group having a rotor drive motor on a baseplate, which, together with an angled front panel, has the operating elements and display instruments typical in laboratory centrifuges. The base group is produced from a coherent metal plate, in which at least two parallel rows of decoupling slots are located in the curved area of the metal plate adjoining the front panel and the baseplate, which form a meandering web connection between front plate and baseplate, whereby a noise development or structure-borne noise caused by imbalance on the rotor is significantly reduced in the direction of the front plate. Furthermore, the integration of sound-reducing materials in the area of the centrifuges is known. For this purpose, for example, DE 72 24 033 U1 proposes the use of a polyurethane hard foam which also acts, inter alia, as a sound barrier. A sound barrier is to be understood in the scope of the invention as an apparatus in a centrifuge which reduces or even prevents the propagation of noise in at least one spatial direction.
However, it has been shown that the noise development of centrifuges is still comparatively high in spite of the preceding measures and is still perceived as annoying. It is therefore the object of the invention to disclose possibilities for reducing the noise development of a centrifuge, in particular an air-cooled laboratory centrifuge, still further.